Prior art devices for elevating objects, human patients or animals from a lowered position to an elevated position have generally been designed for a single specific purpose and usually are confined to a specific range of adjustment between a lower and an elevated position. For example, in the medical field, a patient stretcher used in ambulances is generally adapted for adjustment between a lowered position in which a patient can be lifted onto the stretcher with minimal lifting or handling and a higher, second position to facilitate transfer to an ambulance. Stretchers are also normally suitable for transporting the patient from the ambulance to a hospital bed. The stretchers have only a small range of height adjustment which usually necessitates lifting the patient from the ground surface onto the stretcher. While the stretcher can be used for transporting the patient, the patient must ultimately be lifted a second or even a third time to transfer the patient to a bed or an operating table which is at a more convenient height for treatment. For patients suffering from broken bones and/or internal injuries, such additional handling for transporation and lifting purposes may create further injuries.
Many machinist's tables employ a scissors linkage mechanism but because enormous weights must sometimes be lifted, these tables are often extremely heavy and complex in construction. Moreover, the complexity of the tables mitigates against medical usage, as it is often difficult to thoroughly clean such tables. Greasy, oily or otherwise unsanitary mechanisms are often exposed between the upper and lower platforms, making the device unsuitable for either hospital or veterinary use.